The invention relates to a dishwasher, in particular a household dishwasher.
Dishwashers have filter systems, by means of which dirt particles can be filtered out of the washing liquid that circulates in a hydraulic circuit of the dishwasher. The filter systems generally have more than one stage and consist of a flat fine filter, a coarse filter and optionally a microfilter. Corresponding to their designations, these filters can filter out dirt particles of different sizes from the washing liquid.
For example, DE 31 14 663 A1 discloses a dishwasher that has a hydraulic circuit in which washing liquid circulates and collects in a pump sump at the bottom, wherein said pump sump is attached to the induction side of the circulation pump. The open side of the pump sump, said side being oriented towards the dishwasher interior, is covered by a flat filter which tapers in the form of a funnel towards a hollow cylindrical coarse filter that is arranged approximately centrally. This coarse filter leads to a likewise hollow cylindrical microfilter beneath the flat filter, said microfilter being surrounded at a distance by a sump wall of the pump sump.
The filter system consisting of the flat filter, the coarse filter and the microfilter becomes dirty over time, meaning that the flat filter, the coarse filter and/or the microfilter can become clogged with food residues or other particles that are deposited thereon. Clogged filter surfaces adversely affect the washing results, primarily due to resoiling and reduced filter performance. In some cases, the lower spray arm under the rack can already feature nozzles that are directed at the flat filter beneath them. However, it is not possible to rinse the flat filter completely clean in this way.